This invention relates to knives, and more particularly to utility knives that are used for cutting high density materials, such as ropes, cables and the like.
Knives with serrated cutting edges are old and well-known in the prior art. The serrated blades are conventionally used in household tools, such as table knives and meat cutting knives and a wide variety of saw blades, straight, circular, and band.
However, other than such saw blades, serrated cutting devices have not proved particularly useful in industrial applications such as, for example, hand cutting of ropes, bundles of twine, and the like. Most often, the cutting implement is in a form of a single edge blade that has a sharp edge formed along one edge, while the other edge is dull to protect the user's hand. Such blades are particularly ineffective when a user needs to cut through a thick rope. Small boat operators often encounter a problem when a rope becomes entangled on a propeller or a shaft of a marine vessel and divers have to be called to free the propeller from the shaft to return the vessel to operation.
A rope is a length of fibers, twisted or braided together; it is thicker and stronger than similarly constructed cord, line, string, or twine. Common materials for rope include natural fibers such as Manila hemp, hemp, linen, cotton, coir, jute, and sisal. Synthetic fibers in use for rope-making include polypropylene, nylon, polyesters, polyethylene. Some ropes are constructed of mixtures of several fibers or use co-polymer fibers. Ropes can also be made out of metal fibers. The rope may be constructed in a variety of ways, such as for instance by twisting several strands, by braiding the strands into single or double braids, or by braiding twisted strands for the so-called square braid. Needles to say, the braided and twisted rope are strong, have high tensile strength and are flexible.
While current state-of-art utility knives using single-edge cutting blades are functional in many circumstances, they dull quickly when applied for the cutting of a multi-strand rope, resulting in cutting operations that are laborious and time consuming. The job of cutting a rope under water is even more difficult.
The present invention contemplates elimination of drawbacks associated with the prior art and provision of a utility knife blade that can be beneficial in cutting multi-strand ropes and other such objects, either above or under water.